diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 9bba717708..d57c6d3485 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -946,6 +946,7 @@ static void xen_pci_passthrough_class_init(ObjectClass *klass, void *data)
     k->exit = xen_pt_unregister_device;
     k->config_read = xen_pt_pci_read_config;
     k->config_write = xen_pt_pci_write_config;
+    k->is_express = 1; /* We might be */
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
     dc->desc = "Assign an host PCI device with Xen";
     dc->props = xen_pci_passthrough_properties;